Throughout my career, my research and teaching have revolved around a single broad theme: the scientific study of human cognition. I have concentrated most extensively on the development of cognitive processes in normal and atypical children, but I have also published considerable research on adult cognition and have taught widely in that area. In recent years, my research and teaching have also encompassed questions about how cognitive processes are affected by normal aging and by the diseases of late adulthood. This, in turn, has stimulated a research program in cognitive neuroscience. Across all of these areas, a particular focus has been the relationship between memory processes and higher reasoning abilities. After several years of research and teaching on the memory/reasoning interface, I began to develop, with the collaboration of my colleague V. F. Reyna, a general model of how memory influences reasoning and how reasoning influences memory, which is known as fuzzy-trace theory. Fuzzy-trace theory, which seeks to explain some of the most counterintuitive aspects of memory and reasoning, is now widely used by investigators in fields such as forensic psychology, judgment and decision making, and human memory.